Examine source code of BumBan

{
  "name": "BumBan",
  "version": "1.0",
  "description": "My first extension that bans user from certain chosen behaviours",
  "browser_action": {
    "default_popup": "popup/popup.html",
    "default_icon": "icon/firefox/128.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "permissions": [
    "storage",
    "tabs"
  ],
  "icons": {
    "16": "icon/firefox/16.png",
    "48": "icon/firefox/48.png",
    "128": "icon/firefox/128.png"
  },
  "manifest_version": 2
}